drm/i915/psr: Don't enable Panel Replay on sink if globally disabled

drm/i915/psr: Don't enable Panel Replay on sink if globally disabled

With some panels informing support for Panel Replay we are observing
problems if having Panel Replay enable bit set on sink when forced to use
PSR instead of Panel Replay. Avoid these problems by not setting Panel
Replay enable bit in sink when Panel Replay is globally disabled during
link training. I.e. disabled by module parameter.

The enable bit is still set when disabling Panel Replay via debugfs
interface. Added note comment about this.

Fixes: 68f3a505b367 ("drm/i915/psr: Enable Panel Replay on sink always when it's supported")
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: <stable@vger.kernel.org> # v6.15+
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patch.msgid.link/20260115070039.368965-1-jouni.hogander@intel.com